Medical tube clearance device

ABSTRACT

Methods and devices for actuating a clearance device to clear obstructive debris from medical tubes are disclosed. More particularly, a shuttle that includes a first primary magnetic element that is adapted to magnetically engage and translate a magnetic guide within a tube is disclosed. The first primary magnetic element is aligned so that a first primary magnetic field emanating therefrom is aligned substantially perpendicular to a longitudinal axis of the tube when viewed from a side of the shuttle.

TECHNICAL FIELD

This application relates generally to a medical tube assembly and, morespecifically, to a device for clearing obstructions from a medical tubeof the medical tube assembly.

BACKGROUND

Medical tubes can be used to deliver fluids or devices into a patient'sbody and/or to drain bodily fluids and secretions from compartments andstructures within the body. For example, medical tubes can be used todrain fluid from one's bladder, from the colon or other portions of thealimentary tract, or from the lungs or other organs in conjunction withvarious therapies. As another example, medical tubes can be used todrain blood and other fluids that typically accumulate within a bodycavity following traumatic surgery. As yet another example, medicaltubes can be used to deliver fluids to a patient's body for nourishmentor they can be used to provide access to the vasculature for removal ordelivery of fluids or devices. Typically, a medical tube is insertedinto the patient so that its distal end is provided in or adjacent thespace where it is desired to remove or deliver material while a proximalportion remains outside the patient's body, where it can be connected,for example, to a suction source.

Fluids passing through a medical tube (particularly those includingblood or blood platelets) can form clots or other obstructions withinthe medical tube, which can partially or totally obstruct the suctionpathway within the tube. Obstruction of the medical tube can impact itseffectiveness to remove or deliver the fluid and other material forwhich it was originally placed, eventually rendering the medical tubepartially or totally non-functional. In some cases, a non-functionaltube can have serious or potentially life-threatening consequences. Forexample, if there is a blockage in a chest tube following cardiac orpulmonary surgery, the resulting accumulation of fluid around the heartand lungs without adequate drainage can cause serious adverse eventssuch as pericardial tamponade and pneumothorax.

U.S. Pat. No. 7,951,243, incorporated herein by reference, discloses aclearance device for clearing medical tubes (such as chest tubes) ofobstructive clot material. That device utilizes a shuttle fitted over aguide tube to actuate a clearance member within the tube via a magneticcoupling between the shuttle and a magnetic guide linked to a guide wire(and corresponding clearance member) within the tube. Based on thearrangement of magnetic elements in the shuttle and the magnetic guide,it is possible for the shuttle to become uncoupled from the magneticguide during use. For example, this decoupling may occur when there isan obstruction such as a kink or significant clot material in themedical tube such that drag on the guide wire within the tube isstronger than the magnetic-coupling force between the shuttle and themagnetic guide. The embodiments disclosed here address such decouplingand provide improved magnetic coupling between the shuttle and themagnetic guide.

SUMMARY

According to a first aspect, a device for clearing obstructions from amedical tube is disclosed. The device includes a shuttle defining a tubepassage configured to accommodate a tube therein and adapted totranslate along a length of the tube when accommodated in the passage.The shuttle includes a first primary magnetic element aligned so that afirst primary magnetic field axis of a first primary magnetic fieldthereof is aligned substantially perpendicular to a longitudinal axis ofthe tube passage when viewed from a side of the shuttle.

According to a second aspect, a device for clearing obstructionsincludes a shuttle adapted to translate along a length of a tube. Theshuttle includes a passage body defining a tube passage having alongitudinal axis configured to accommodate a tube therein. A firstprimary-magnet recess is disposed in the passage body outside the tubepassage. A first primary magnetic element is received in the firstprimary-magnet recess and has a first primary magnetic field emanatingalong a first primary field axis that is radially aligned relative tothe aforementioned longitudinal axis. A button is operable to slidablyadjust the first primary magnetic element within the firstprimary-magnet recess between a first position radially remote from thetube passage, and a second position radially proximate the tube passage.

According to a third aspect, a method of clearing obstructions from amedical tube is disclosed. The method includes translating a shuttledisposed outside of a tube along a length thereof to correspondinglytranslate an elongate guide member that is at least partially disposedwithin the tube and magnetically coupled to the shuttle member through awall of the tube. A magnetic field emanating from the shuttle is alignedsubstantially perpendicular to a longitudinal axis of the tube whenviewed from a side of the shuttle.

According to a fourth aspect, a device for clearing obstructionsincludes a shuttle defining a tube passage configured to accommodate atube therein and adapted to translate along a length of the tube whenaccommodated in the passage. A first primary magnetic element of theshuttle is adjustable in order to adjust a coupling strength between thefirst primary magnetic element and a magnetic guide disposed within thetube when received through the tube passage.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective illustration showing a clearancedevice coupled to a medical tube (e.g., a chest tube) that has beenplaced in a patient, to permit clearance of the medical tube ofobstructions formed therein.

FIG. 2 is a partially sectioned view of a clearance device;

FIGS. 3A and 3B are schematic representations of magnetic fields betweenmagnetic elements in a magnetic guide and magnetic elements in a shuttleof a clearance device for clearing obstructions from a medical tube.FIG. 3A illustrates a first arrangement of the magnetic elements, andFIG. 3B illustrates a second arrangement of the magnetic elementsaccording to embodiments disclosed herein.

FIG. 4 is a side view of a clearance device having a shuttle accordingto an example embodiment hereafter described;

FIG. 5 is a perspective view of the shuttle in the clearance device ofFIG. 4;

FIG. 6A is a partially exploded view of the clearance device of FIG. 4;

FIG. 6B is a close-up view of a magnetic guide of the clearance deviceof FIG. 4 shown at B in FIG. 6A;

FIG. 7 is an exploded view of the shuttle in FIG. 5;

FIG. 8 is a further partially-exploded view of the shuttle in FIG. 5,with the entire housing of the shuttle removed;

FIG. 9 is a close-up exploded view showing an arrangement of secondarymagnetic elements and a secondary shield of the shuttle in FIG. 5, withother elements of the shuttle removed;

FIG. 10 is a close-up exploded view showing an arrangement of drivemagnets, a drive shield, a spring, and a button of the shuttle in FIG.5, again with other elements of the shuttle removed;

FIG. 11 is a perspective, lateral cross-sectional view of the shuttletaken along the line A-A in FIG. 5;

FIG. 12 is a cross-sectional view of the shuttle taken along the lineB-B in FIG. 5;

FIG. 13 is a perspective, lateral cross-section view showing the drivemagnets of the shuttle in FIG. 5 in a first position, opposite thesecondary magnetic elements relative to a tube passage 40, with otherportions of the shuttle removed;

FIG. 14 is a perspective, cross-section view as in FIG. 13 with thedrive magnets in a second position;

FIG. 15 is a perspective, cross-sectional view of shuttle according toan alternative embodiment;

FIGS. 16-18 are perspective views of a clearance device coupled to achest tube schematically showing the shuttle, and correspondingly theguide wire and clearance member, at different stages of advancement forclearing obstructions from the chest tube, ranging from fully advancedin FIG. 16 to fully withdrawn in FIG. 18.

DETAILED DESCRIPTION

Certain terminology is used herein for convenience only and is not to betaken as a limitation on the present invention. Relative language usedherein is best understood with reference to the drawings. Further, inthe drawings, certain features may be shown in schematic form.

It is to be noted that the terms “proximal” and “distal” as used hereinwhen describing two ends or portions of a feature indicate a relativepositioning that those two ends or portions will generally have along anin-line system relative to a patient, the distal end or portion beingcloser to (or more advanced within) the patient than the proximal end orportion. For example, in an in-line system comprising a tube that drawsfluid from the patient through the tube along a flow path, a distal endor portion of the tube will be closer to (likely implanted within) apatient than a proximal end or portion, which will be outside thepatient along the flow path of the fluid.

Examples will now be described more fully hereinafter with reference tothe accompanying drawings in which example embodiments are shown.However, aspects may be embodied in many different forms and should notbe construed as limited to the embodiments set forth herein.

FIG. 1 shows a schematic representation of a medical tube used to drainaccumulated fluid from within a body cavity of a patient, in accordancewith an example embodiment. In FIG. 1 the medical tube is inserted intoand used to drain fluid from the chest cavity of the patient, and canbe, e.g., a chest tube 10 described in the '243 patent incorporatedabove. The remaining description will be provided with reference to achest tube 10. However, other body tubes used in other applicationscould also be used with the embodiments as described herein.

Returning to FIG. 1, the chest tube 10 enters the patient through thechest-cavity (body) wall, so that its distal end is positioned withinthe chest (body) at a location from which fluid is to be drained. Theproximal end of the chest tube 10 remains outside the body. The chesttube 10 can be inserted into the patient in a conventional manner andpositioned and secured in place through the chest-cavity wall by aphysician. A clearance device 100 is fitted to the proximal end of thechest tube 10. The clearance device 100 can include a shuttle guide tube110 (described below) that is connected to the proximal end of the chesttube 10 and is provided in fluid communication therewith. The clearancedevice 100 also includes a clearance member 124 that can be reversiblyadvanced into and through the chest tube 10 to withdraw obstructivedebris therefrom (also described below). The proximal end of the shuttleguide tube 110 (i.e., the end opposite the point of connection to thechest tube 10) is connected to a suction source 200, e.g., via a vacuumtube 210. The suction source draws a suction within the chest tube 10,via the shuttle guide tube 110 (if present) and vacuum tube 210 (ifpresent), both to draw fluid out of the body cavity and to sustain thenormal physiologic negative pressure within the chest.

An example clearance device 100 will now be more fully described. Asseen in FIG. 2, the clearance device 100 can include the shuttle guidetube 110 mentioned above. The shuttle guide tube 110 has a proximal end111 and a distal end 112. In use, the proximal end 111 of the shuttleguide tube 110 is adapted to be connected to a suction source,preferably via a suction fitting 90 secured to its proximal end, and thedistal end 112 is adapted to be connected to a medical tube, such as thechest tube 10, preferably via a chest-tube fitting 92 secured to itsdistal end. Guide tube 110 has a wall having an inner diameter 114defining a guide-tube passageway 116 and an outer circumference 118. Ashuttle 20 may be selectively fitted over the guide tube 110 at itsouter circumference 118 and is adapted to translate along the length ofthe tube 110 to advance and withdraw the clearance member 124 asdescribed in detail below. In FIGS. 1, 2 and 15-17 the shuttle 20 isschematically represented. FIGS. 4-14 (described in detail below)illustrate an example embodiment of shuttle 20.

A wire clearance assembly 120 is at least partially disposed within theguide-tube passageway 116. The wire clearance assembly 120 includes anelongate guide member 122 and a clearance member 124 disposed in andsecured to the distal region of the guide member 122, preferably at itsdistal end. In one embodiment, the guide member 122 can be in the formof a guide wire, and the clearance member 124 can be formed by the guidewire, e.g., as a loop. A magnetic guide 130 (e.g., permanent magnets) issecured to the guide member 122 preferably in the proximal regionthereof.

As will be evident in FIG. 2, the shuttle 20 magnetically couples to themagnetic guide 130 via outer magnetic elements 142 located within orassociated with the shuttle 20. Magnetic elements 142 shown in FIG. 2,can be the primary magnetic elements 27 and secondary magnetic elements28 (see FIG. 7) as later described. When the North and South poles ofthe outer magnetic elements 142 are aligned axially, generally parallelto the corresponding (but typically oppositely-oriented) poles of themagnets 132 of the magnetic guide 130, the resulting cooperatingmagnetic fields between the outer magnetic elements 142 in the shuttle20 and the magnetic guide 130 are parallel as shown schematically inFIG. 3A.

For magnets of a given magnetic-field strength, such parallel magneticfields, as shown in FIG. 3A, sometimes may not strong enough to resistdecoupling the shuttle 20 from the magnetic guide 130 when the guidemember 122 (or the clearance member 124 attached thereto) encounters arobust obstruction within the medical tube 10, which produces dragagainst which the guide member 122 must translate. When the clearancemember 124 encounters such an obstruction, sufficient force must beapplied to the clearance member 124 in the X-direction (FIG. 2) toovercome the resistance (drag) provided by the obstruction. When theclearance member 124 engages debris within the chest tube 10, if theamount of force required to move through the debris exceeds theX-direction component of the magnetic coupling force between themagnetic guide 130 and the outer magnetic elements 142 duringtranslation of the shuttle, then decoupling between the shuttle 20 andthe magnetic guide 130 occurs.

Such a loss of magnetic coupling between the shuttle 20 and magneticguide 130 may also occur if a kink in the chest tube 10 producessufficient drag on the guide member 122 to overcome the X-directionmagnetic-coupling force, or for any number of other reasons. While themagnetic coupling may be restored by returning the shuttle 20 toproximity with the magnetic guide 130, one still can face decoupling ifthe reason they became decoupled persists (as in the case of anobstruction).

FIGS. 4-14 illustrate a clearance device having an example shuttle 20,which yields strong coupling with the magnetic guide 130 through thewall of, e.g., a shuttle guide tube 110. As seen in FIG. 4, theclearance device 100 can include a shuttle guide tube 110 as mentionedabove having a proximal end 111 and a distal end 112. In use, theproximal end 111 of the shuttle guide tube 110 is adapted to beconnected to a suction source preferably via a suction fitting 90secured to its proximal end, and the distal end 112 is adapted to beconnected to a medical tube, such as a chest tube 10, preferably via achest-tube fitting 92 secured to its distal end. In an alternativeembodiment, not shown, the distal end 112 of the guide tube 110 can beconnected to the medical tube via a branched fitting, such as a teefitting or Y-fitting, wherein guide tube 110 will form a lateral branchoff of the main suction circuit defined between the medical tube and asuction source (e.g. via vacuum tube 210) in communication with a thirdport of the branched fitting. In this manner, the guide wire (discussedbelow) will be retracted through the guide tube 110 laterally out fromthe main suction circuit through which secretions are suctioned from themedical tube. Regardless of the particular guide-tube installation (i.e.whether in-line or as a branch off of the main suction circuit, theshuttle 20 is disposed over, preferably in contact with, the wall of theguide tube 110 at its outer circumference 118 (see FIG. 2) and isadapted to translate along the length of the tube 110 in the X-directionto advance and withdraw a wire clearance assembly 120 as describedbelow.

A shuttle stop 150 is secured to the outer circumference 118 of theguide tube 110 in a distal region thereof, preferably just proximal tothe distal end of the guide tube 110. The shuttle 20 and shuttle stop150 can have complementary first and second surfaces that face oneanother. As the shuttle 20 is translated distally along the length ofthe guide tube 110, the shuttle 20 approaches and ultimately reaches aposition wherein the respective first and second surfaces are in contactor disposed adjacent one another. This represents the distal-mostposition for the shuttle 20, and therefore the greatest degree of distaladvancement of the clearance member 124 within the medical tube 10.Preferably, the position of the shuttle stop 150 is selected,corresponding with the length of the guide member 122, to ensure thatthe clearance member 124 does not emerge from the distal end of themedical tube 10 in-use.

The wire clearance assembly 120 is configured to be at least partiallydisposed within the guide-tube passageway 116. As seen in FIG. 6A, thewire clearance assembly 120 includes an elongate guide member 122 and aclearance member 124 disposed in and secured to the distal region of theguide member 122, preferably at its distal end. In one example, theguide member 122 can be in the form of a guide wire, and the clearancemember 124 can be formed by the guide wire, which can be wound to form aloop. The remainder of this description is provided with reference to aguide wire as a preferred example of the guide member 122. However,other examples of a guide member 122 are possible and will be readilyascertained by those having ordinary skill in the art.

Still referring to FIG. 6A, a magnetic guide 130 is secured to the guidewire 122, preferably in the proximal region thereof. The magnetic guide130 can comprise one or a plurality of inner magnetic elements 132. Themagnetic elements 132 are considered “inner” magnetic elements becausethey reside within the guide tube 110. Optionally, the inner magneticelements 132 can be permanent magnets. Alternatively, they can be metalelements having magnetic properties, which are not necessarily permanentmagnets. As used herein, a metal element has magnetic properties if itis capable of being attracted by a permanent magnet via magnetic forces.The magnetic guide 130 can be secured to the guide wire 122 via anysuitable or conventional means. FIG. 6B illustrates a close-up view(indicated at “B” in FIG. 6A) of an exemplary magnetic guide 130. Inthis example, a plurality (four are illustrated) of cylindrically shapedinner magnetic elements 132 having axial through bores are coaxiallyaligned adjacent to one another. The inner magnetic elements 132 areoriented such that their respective North and South poles face the samedirection. This results in the inner magnetic elements 132 attractingone another at their adjacent faces. The guide wire 122, extending fromits distal end, passes through the axial bores of the inner magneticelements 132.

As will also be appreciated, where two or more such inner magneticelements 132 are used, it is not necessary that both or all arepermanent magnets or that both or all are not permanent magnets. Theinner magnetic elements 132 may optionally be present as one (or more)of each permanent and non-permanent magnets. However, in examples whereretentive forces between them may be relied upon to hold them in placerelative to the guide wire 122, using permanent magnets as the innermagnetic elements 132 should produce a stronger attractive force betweenthem, resulting in more securely retaining them to the guide wire 122.

As noted above and most clearly seen in FIG. 4, the shuttle 20 isdisposed over, preferably in contact with, the outer circumference 118of the guide tube 110. The shuttle 20 has a tube passage 40 preferablyin the form of a through bore having a diameter substantiallycorresponding to the outer circumference 118, such that the shuttle 20can slidably and smoothly translate along the length of the guide tube110 when that tube is received through its tube passage 40. The shuttle20 includes a shuttle housing, which in the illustrated embodiment (FIG.7) is formed of opposing first and second clamshell halves 21 and 22that form the exterior body of the shuttle 20. A depressible button 23is accessible through, e.g., stands proud of, the shuttle housing and isused to actuate drive magnets 27 as described below.

As illustrated in FIG. 7, the shuttle 20 includes a passage body 24,which defines the aforementioned tube passage 40 to accommodate theguide tube 110 (or the medical tube 10 in embodiments where a guide tube110 is not used). Alternatively, the tube passage 40 may accommodate avacuum tube 210; e.g. if no separate guide tube 110 is interposedbetween the vacuum tube 210 and the medical tube 10. The tube passage 40in the passage body 24 preferably has an inner surface that iscomplementary and substantially corresponds to the outer perimeter shapeof the guide tube 110, or in the case of a cylindrical tube, its outercircumference 118. One or a plurality of primary-magnet recesses 33 (twoare illustrated) are formed in an outer portion of the passage body 24,outside the tube passage 40, and are distributed in longitudinalalignment with the tube passage 40. The recesses 33 preferably arealigned such that respective longitudinal (magnetic-field) axes ofmagnetic elements to be received therein will be perpendicular to andintersect the longitudinal axis of the tube passage 40. One or aplurality of primary magnetic elements 27 (e.g., drive magnets) arereceived within the respective recesses 33 of the passage body 24. Inthe illustrated example, the primary magnetic elements 27 arecylindrical. In other examples, the primary magnetic elements 27 may beany shape that is suitable to fit within the primary-magnet recesses 33of the passage body 24. Those recesses 33 may be of any desirable shape.

As with the inner magnetic elements 132 discussed above, the primarymagnetic elements 27 can be permanent magnets or, alternatively, metalelements having magnetic properties that are not necessarily permanentmagnets. However, for reasons that will become clear, either at leastone of the inner magnetic elements 132 or at least one of the primarymagnetic elements 27 should be a permanent magnet. In preferredexamples, both the inner and primary magnetic elements 132 and 27 arepermanent magnets. Further, the magnetic guide 130 and the primarymagnetic elements 27 may have a residual flux density (Br) of, e.g.,14-15 kGs, such as 14.3 to 14.8 kGs.

FIG. 3B schematically illustrates the arrangement of the inner magneticelements 132 (e.g., of magnetic guide 130) and the primary magneticelements 27 when the latter are arranged as in the embodiment of theshuttle illustrated in FIG. 7. (FIG. 3B also illustrates secondarymagnetic elements 28, which will be further described below). As seen inFIGS. 3B and 7, the primary magnetic elements 27 (housed in the shuttle20) preferably are aligned radially relative to the tube passage 40 suchthat the North and South poles of each are aligned along a radius of thetube passage 40 (and an axis of the particular primary magnetic element27 when cylindrical) that intersects that passage's longitudinal axis.When two primary magnetic elements 27 are used as drive magnets, theyare arranged such that their respective North and South poles faceopposite directions. In other words, the North pole of one primarymagnetic element 27 faces the tube passage 40 while the South pole ofthe other primary magnetic element 27 faces the tube passage 40. Thisresults in the two primary magnetic elements 27 creating a single Northpole and a single South pole facing the guide tube 110 when received inthat passage 40 along a segment thereof defined by the longitudinalspacing of the primary magnetic elements 27. In this manner, and as willbe explained further below with respect to FIG. 3B, the resultingmagnetic fields from the primary magnetic elements 27 can propagate andbe aligned substantially perpendicular to the magnetic field of (andtoward) the magnetic guide 130, as opposed to parallel therewith. It isdesirable that the spacing between the primary magnetic elements 27 issuch that their respective longitudinal (or magnetic-field) axes aresubstantially aligned with, and preferably intersect, the respectiveNorth and South pole ends of the magnetic guide 130 along a longitudinalaxis of the magnetic guide 130. Preferably, the South pole of firstprimary magnetic element 27 faces the North pole of the magnetic guide130, and the North pole of a second primary magnetic element 27 facesthe South pole of the magnetic guide 130.

As illustrated in FIGS. 7 and 9, the shuttle 20 further includes one ora plurality of secondary magnetic elements 28 radially opposing theprimary magnetic elements 27 relative to the tube passage 40 of thepassage body 24. Preferably, the secondary magnetic elements 28 arereceived within corresponding secondary-magnet recesses 34 formed in anouter portion of the passage body 24, outside the tube passage 40,opposing the respective primary-magnet recesses 33 and aligned therewithalong common radial axes relative to the passage 40. In the illustratedexample, the secondary magnetic elements 28 are cylindrical. In otherexamples, the secondary magnetic elements 28 may be any shape that issuitable to fit within the secondary-magnet recesses 34 of the passagebody 24. The secondary magnetic elements 28 also can be permanentmagnets or, alternatively, metal elements having magnetic propertiesthat are not necessarily permanent magnets. However, for reasons thatwill become clear, either at least one of the inner magnetic elements132 or at least one of the secondary magnetic elements 28 should be apermanent magnet. In preferred examples, both the inner and secondarymagnetic elements 132 and 28 are permanent magnets. Further, themagnetic guide 130 and the secondary magnetic elements 28 may have aresidual flux density (Br) of, e.g., 14-15 kGs, such as 14.3 to 14.8kGs.

In preferred embodiments, the secondary magnetic elements 28 will belongitudinally spaced similarly as (i.e., so that their respective axesalign and are co-axial with), but oriented oppositely to, the opposingprimary magnetic elements 27. That is, the North/South-pole orientationof each secondary magnetic element 28 should be opposite that of itsopposing primary magnetic element 27, so that opposing poles of therespective opposing primary and secondary magnetic elements 27 and 28face each other opposite the tube passage 40.

As with the primary magnetic elements 27, the secondary magneticelements 28 are aligned radially relative to the tube passage 40 suchthat the North and South poles of each secondary magnetic element 28 arealigned along a radius of the tube passage 40 (and an axis of theparticular secondary magnetic element 28 when cylindrical) thatintersects that passage's longitudinal axis. Thus, similarly as aboveand explained further below with respect to FIG. 3B, the resultingmagnetic fields from the secondary magnetic elements 28 will propagateand be aligned substantially perpendicular to the magnetic field of (andtoward) the magnetic guide 130, as opposed to parallel therewith.Preferably, each secondary magnetic element 28 also is aligned along acommon radial axis (relative to the tube passage 40) with an opposingprimary magnetic element 27 so that their opposing magnetic fields arealigned along their common radial axis and propagate toward one anotherthrough the passage body 24.

In the illustrated embodiments, only one set of opposing primary- andsecondary magnets 27 and 28 is provided, aligned along a single radiusof the tube passage 40 when viewed end-on (i.e. along the longitudinalaxis of that passage 40). However, optionally a plurality of sets ofopposing primary- and secondary magnets 27 and 28 may be distributedcircumferentially relative to the tube passage 40, aligned alongrespective, circumferentially indexed radii of that passage 40—i.e. suchthat circumferentially adjacent ones of the respective radii woulddefine an arc sector of the passage 40 when viewed end-on along thelongitudinal axis thereof. For example, two sets of opposing primary-and secondary magnets 27 and 28 may be provided, wherein each set isaligned along a respective radius of the tube passage 40 perpendicularto the radius along which the other set is aligned—so that the two radiidefine four equal-quadrant arc segments of the tube passage 40 whenviewed end-on along its longitudinal axis.

The opposing primary- and secondary magnetic elements 27 and 28 providea strong magnetic coupling to the magnetic guide 130 attached to theguide member 122 within the guide tube 110 (or medical tube 10) to drivethe guide member 122 within that tube via translation of the shuttle 20outside the tube 110, as will be further explained. To reduceinterference with surrounding electronic medical equipment or implantedmedical devices, the shuttle 20 may incorporate magnetic shielding(e.g., within its housing). For example, a primary magnetic shield 25can be disposed over exposed surfaces of the primary magnetic elements27, between them and the button 23 used to adjust them between first andsecond positions as will be described. Similarly, a secondary magneticshield 29 can be provided over the exposed surfaces of the secondarymagnetic elements 28 (e.g., covering them within the secondary-magnetrecesses 34). As illustrated in FIGS. 7 and 8, the shuttle 20 furthercan include lateral shielding 30 surrounding the primary- and secondarymagnetic elements 27 and 28 within the shuttle 20. As shown, the lateralshielding 30 can be a U-shaped element that extends from one side of thepassage body 24 to the opposing side of the passage body 24, around anend of the passage body 24. The lateral shielding 30 includes apertures31 dimensioned to fit over protuberances 32 that extend from opposingsides of the passage body 24 (e.g., from fins 35 formed therein). Byaligning the lateral shielding 30 so that the protuberances 32 aresecured within apertures 31, appropriate and secure alignment of theshielding 30 can be assured.

The fins 35 extend laterally from the passage body 24 and aredimensioned to appropriately seat the lateral shielding 30 uniformlyadjacent to the passage body 24 at a predetermined distance from theprimary- and secondary magnetic elements 27, 28. This is useful when theshielding 30 is made of a ferromagnetic material (e.g. low-carbonsteel), which in the absence of such fins 35 to correctly seat it andpreserve its shape could be drawn and deformed by the magnetic fields ofthe primary- and secondary magnets 27 and 28. The fins 35 and theirassociated protuberances also facilitate proper, reproducible alignmentand securement of the lateral shielding 30 over the passage body 24 toprevent mis-alignment. Moreover, by fixing the seating position andorientation of the lateral shielding 30, the fins 35 ensure that theshielding 30 remains uniformly spaced from, and does not touch, themagnets 27, 28 or any field-conductive structures communicating with themagnets, which might produce field-shunting. Instead, spaced asdescribed, the lateral shielding 30 will provide far-field magneticshielding to substantially confine the magnetic fields within theshuttle and minimize escape of those fields.

The primary and secondary magnetic shields 25, 29 and the lateralshielding 30 are preferably made of low-carbon steel. In other examples,they can be made of any material with a high-iron content, e.g.conventional Mu-Metal materials as known in the art. As will beappreciated, the primary magnetic shield 25, secondary magnetic shield29 and lateral shielding 30 cooperate to magnetically shield theprimary- and secondary magnets 27 and 28 within the shuttle 20,inhibiting the propagation of their magnetic fields beyond the shuttle20. While the combined shielding as described cannot completely enclosethe magnetic elements 27 and 28 (because they must magnetically interactwith the magnetic guide 130, and accommodate the tube passage 40), itwill help to reduce the propagation and strength of the magnetic fieldsbeyond the shuttle 20. It also is noted that when the shuttle 20 isfitted over a tube and aligned with the magnetic guide 130 therein, thecombined shielding as described also shields the fields emanating fromthe magnetic guide 130 (now disposed within the shuttle 20), effectivelyinternally redirecting the combined magnetic fields emanating from thecomplete magnetic circuit encompassing the interacting primary- andsecondary magnetic elements 27 and 28 with the magnetic guide 130. As aresult, magnetic-coupling force with the magnetic guide 130 may beincreased.

It has been found that adjusting the thickness of the primary andsecondary magnetic shields 25, 29 (e.g. made of low-carbon steel) canimpact the magnetic-coupling strength with the magnetic guide 130. Forexample, increased thickness of the primary magnetic shield 25 willresult in greater shunting of the respective magnetic fields from oneprimary magnetic element 27 to the other; effectively helping to drivethe combined primary magnetic fields radially inward toward the tubepassage 40 axis (and the magnetic guide 130). This will tend tostrengthen the coupling force between the primary magnetic elements 27and the magnetic guide 130 within a tube received through the tubepassage 40. Similarly, increased thickness of the secondary magneticshield 29 will yield greater shunting of the respective magnetic fieldsbetween the secondary magnetic elements 28. This will reinforce themagnetic coupling between the secondary magnetic elements 28 and themagnetic guide 130. It may be useful to tune the respective primary andsecondary magnetic shield 25,29 thicknesses in order to optimizecoupling with the magnetic guide 130. That is, increased coupling forcebetween the primary magnetic elements 27 and the magnetic guide 130 mayyield stronger available translational (axial) force to the guide member122 (and clearance member 124) attached to the magnetic guide 130, viatranslation of the shuttle 20. However, such increased coupling forcealso will increase transverse (radial) forces between the magnetic guide130 and the inner diameter of the tube wall, leading to increasedfriction. Increasing coupling force between the secondary magneticelements 28 and the magnetic guide 130 may lessen that effect by drawingthe magnetic guide 130 away from the tube wall adjacent to the primarymagnetic elements 27. By tuning the relative thicknesses between theprimary and secondary magnetic shields 25, 29, these competing effects(available translational force through coupling, versus friction) may beoptimized. For low-carbon steel, shield thickness preferably is withinthe range of 0.01 to 0.25 inches, more preferably 0.025 to 0.175 inchesfor both the primary and secondary magnetic shields 25 and 29.Meanwhile, increasing the thickness of the lateral shieldingindependently can help reduce escaping of the magnetic fields emanatingfrom within the shuttle to the extraneous environment.

FIG. 3B schematically illustrates the primary- and secondary magneticelements 27 and 28 oriented and aligned as disclosed, relative to(example inner magnetic elements 132 of) the magnetic guide 130, andtheir resultant, cooperating magnetic fields. As seen in the figure, themagnetic fields of the primary- and secondary magnetic elements 27 and28 propagate along axes aligned perpendicular with the axis of themagnetic field emanating from the magnetic guide 130 (e.g., fromelements 132 thereof). It has been found that with the magnetic fieldsaligned in this fashion, the magnetic attraction between the shuttle 20(via its primary/secondary magnetic elements 27, 28) and the magneticguide 130 can be quite strong, resulting in improved coupling betweenthe shuttle 20 and the magnetic guide 130 during use. Accordingly, moreforce may be applied to the clearance member 124 in the X-directionwithout decoupling the shuttle 20 from the magnetic guide, in order toovercome drag resistance introduced by an obstruction encountered by theclearance member 124 within the chest tube 10.

For example, a conventional shuttle 20 having high field-strengthrare-earth, neodymium magnets configured as rings as described in the'243 patent, coupled to similar-composition neodymium magnets in themagnetic guide 130, typically delivers approximately 0.4 lbf oftranslational force to the clearance member 124 in the X-directionbefore the shuttle 20 becomes decoupled from the magnetic guide 130.This is the amount of force available to overcome drag introduced by anobstruction in the medical tube 10. Whereas using the primary- andsecondary magnetic elements 27 and 28 aligned to orient their opposingmagnetic fields radially toward the magnetic guide 130 against asimilarly constituted magnetic guide 130 as disclosed here, the shuttle20 herein has been shown to deliver up to approximately 1.2 lbf oftranslational force to the clearance member 124 before decoupling fromthe magnetic guide 130; i.e., about three times the availabletranslation force compared to the prior-art device. The increasedavailable translational force is a result of stronger magneticattraction between the magnetic elements in the shuttle 20 and those inthe magnetic guide 130 during use, believed to be a result of orientingthe primary- and secondary magnetic elements 27 and 28 as hereindisclosed. The result is greater ability to overcome and clear robustobstructions in the medical tube 10, and reduced incidence ofshuttle-decoupling.

Further, it is believed that both the primary- and secondary magneticshields 25 and 29 help to strengthen the effective magnetic attractionbetween the primary and secondary magnetic elements 27 and 28,respectively, and the magnetic guide 130. Specifically, the primarymagnetic shield 25 couples the opposing poles of adjacent primarymagnetic elements 27, which reinforces their magnetic fields bycompleting a circuit between the primary magnetic elements 27. Thesecondary magnetic shield 29 acts in a similar manner to reinforce themagnetic fields of the secondary magnetic elements 28 by completing acircuit therebetween. This results in a greater ability to overcome andclear obstructions in the medical tube 10, and reduced incidence ofshuttle-decoupling.

As will be appreciated, the maximum available magnitude of the strongmagnetic coupling between the shuttle 20 and the magnetic guide 130through the tube wall will not be necessary at all times to translatethe clearance member 124. For example, in the absence of obstructions orin the presence of minor obstructions, minimal coupling force may berequired to translate the clearance member 124. In such instances,maximum coupling force between the shuttle 20 and the magnetic guide 130may be undesirable, because it will increase the frictional forceagainst sliding the shuttle 20 along the tube 110, thus making thedevice 100 more cumbersome to use routinely. It also will increase thefrictional force between the internal magnetic guide 130 and the ID ofthe tube 110. Accordingly, the shuttle 20 includes a mechanism tooperate at reduced magnetic coupling strength, and to increase themagnitude of the coupling strength to a maximum degree only when desiredby the operator to clear or traverse a robust obstruction in the medicaltube 10.

Specifically, as illustrated in FIGS. 7 and 10 and noted above, theshuttle 20 includes the depressible button 23, e.g., arranged on a faceof the primary magnetic shield 25 opposite the primary magnetic elements27. In one example, the button 23 includes a boss 36 that extends fromits underside through a central aperture 37 in the primary magneticshield 25, and through a spring 26 positioned between the primarymagnetic elements 27. Opposite the primary magnetic shield 25, thespring 26 is seated and rests against the passage body 24, e.g., withina radial passage or spring recess 38 defined between the primary-magnetrecesses 33. In this manner, the spring 26 biases the primary magneticshield 25 and the button 23 at its opposite face in a position radiallyremote from the passage body 24. Preferably, the primary magneticelements 27 are adhered (e.g. via magnetic interaction) to the undersidesurface of the magnetic shield, so that the primary magnetic elements 27are similarly biased radially away from the tube passage 40,corresponding to a first position of the primary magnetic elements 27(FIG. 13) as hereafter described. Whereas, depressing the button 23radially inward drives the primary magnetic shield 25 and the attachedprimary magnetic elements 27 radially inward, against the spring bias,preferably until they become seated against respective floors of theprimary-magnet recesses 33 in a second position of those elements 27(FIG. 14), also hereafter described.

As illustrated in, e.g., FIGS. 11 and 13, the secondary magneticelements 28 are fixed within the secondary-magnet recesses 34 of thepassage body 24. Conversely, the primary magnetic elements 27 can beadjusted through a range of radial positions relative to the tubepassage 40 of the passage body 24, e.g., between the aforementionedfirst and second positions. Because the radial positions of thesecondary magnetic elements 28 are fixed, the field strength availablefrom the secondary magnetic elements 28 for translating the magneticguide 130 (and thereby the clearance member 124) is not manuallyadjustable. However, one can manually adjust the field strengthavailable from the primary magnetic elements 27 to drive the magneticguide 130 by operating the button 23, thereby adjusting the primarymagnetic elements 27 between the first and second positions as will befurther explained.

Referring to FIG. 13, the primary magnetic elements 27 are shown in thefirst (resting) position. With the magnetic guide 130 disposed withinthe tube passage 40 of the shuttle 20 (inside of the tube 110 receivedtherethrough), the primary and secondary magnetic elements 27, 28 aremagnetically attracted to the magnetic guide 130 from opposing radialdirections. And as the shuttle 20 translates along the guide tube 110,the magnetic attraction between the magnetic elements 27, 28 of theshuttle 20 and the magnetic guide 130 induces movement of the clearancemember 124 within the chest tube 10, e.g., to remove obstructions withinthe chest tube 10. This translational movement with the primary magneticelements 27 in their first (resting) position, remote from the tubepassage 40, generally is sufficient for routine clearing of the chesttube 10 at predetermined intervals.

However, if the clearance member 124 encounters a robust obstructionwithin the chest tube 10, additional force in the X-direction may berequired to traverse or dislodge the obstruction and continuetranslating the clearance member 124 along its course through the chesttube 10. In such instances, the button 23 may be pressed to therebyadvance the primary magnetic elements 27 radially inward, toward or intotheir second position, seated within the respective primary-magnetrecesses 33 adjacent to the tube passage 40. In such radially advanced(e.g., their second) position, the primary magnetic elements 27 becomemore recessed within the recesses 33, closer to the magnetic guide 130within the tube 110 received in the tube passage 40 of the shuttle 20,as illustrated in FIG. 14. When the primary magnetic elements 27 arelocated closer to the magnetic guide 130, the magnetic attraction forcebetween the primary magnetic elements 27 and the magnetic guide 130 isincreased, which enables the shuttle 20 to apply stronger translationalforce to the clearance member 124 in the X-direction before it willdecouple from the magnetic guide 130.

While the primary magnetic elements 27 are shown in the first and secondpositions in FIGS. 13 and 14, it will be appreciated that thosepositions represent the boundaries of the adjustable range. The primarymagnetic elements 27 may be adjusted to any point between thosepositions to yield corresponding adjustment to the strength of themagnetic coupling between primary magnetic elements 27 and the magneticguide 130. For example, if a slight increase of available force in theX-direction is desired, the button 23 can be only slightly depressed,e.g., to reduce the radial distance between the primary magneticelements 27 and the magnetic guide 130 by 10%, 15%, 20%, 25%, or someother fraction less than 100%. If additional force in the X-direction isdesired, the button 23 may be depressed further, e.g., to reduce thatradial distance even further such as by 30%, 35%, 40%, 45%, 50%, ormore. A user may depress the button 23 and decrease the distance betweenthe primary magnetic elements 27 and the magnetic guide 130 by anyamount between the first and second positions of the primary magneticelements 27. The spring 26 biases the button 23 (and primary magneticelements 27) to the fully radially withdrawn (i.e., ‘resting’) position,and thus will oppose any depression of the button 23. In this manner, auser may adjust the degree of field-strength increase by modulating thedegree to which the button 23 is pressed against the spring bias. Andonce the operation is completed, the spring 26 returns the button 23(and primary magnetic elements 27) to the fully radially withdrawn,‘resting’ position.

In one example, the radial (relative to the tube passage 40) distancebetween the primary and secondary magnetic elements 27, 28 (with theprimary magnetic elements 27 fully radially engaged and seated againsttheir floors of the respective primary-magnet recesses) is 0.5 inches,0.75 inches, 0.85 inches, 0.95 inches, or 1 inch; e.g., depending on thediameter of the tube passage 40 adapted to accommodate a particular tube110 therein. By positioning the magnetic guide 130 between the primaryand secondary magnetic elements 27, 28, theoretically the magnetic guide130 could be magnetically, radially suspended in a generally centralposition within the tube 110 inside the tube passage 40. Although thistheoretical possibility typically will not be realized in practice, thefact that the magnetic guide 130 is nonetheless drawn in opposingdirections between the primary- and secondary magnetic elements 27, 28can reduce frictional forces between the magnetic guide 130 and theguide tube passageway as the shuttle 20 is operated to translate theclearance member 124. As a result, the amount of force available forX-direction translation of the clearance member 124 may be increasedupon translation of the shuttle 20 along the tube 110.

In order to maximize the field strength (if that is desired) betweeneither (or both) the primary- and the secondary magnetic elements 27, 28and the magnetic guide 130 within a tube 110 received in the tubepassage 40, the radial distance therebetween should be as small aspossible. In one example, the radial distance between, e.g., the primarymagnetic elements 27 and the magnetic guide 130 can be reduced byintroducing apertures 41 in the base wall of each primary-magnet recess33, thereby effectively reducing the outer diameter of the tube passage40 in the vicinity of the respective recess 33 so that the primarymagnetic elements 27 may be driven radially more inward. This is shownin FIG. 12. By removing a portion of the passage body 24 constitutingthe circumferential wall of the tube passage 40 in the vicinity of therecesses 33, the primary magnetic elements 27 can be seated moreradially inward, nearer to the inner diameter of (or even partiallywithin) the tube passage 40. Also optionally, if desired similarapertures can be provided in the floor of each secondary-magnet recess34 to permit a greater degree of radially-inward fixation of thesecondary magnetic elements 28. However, in practice such apertures inthe floors of the secondary-magnetic recesses 34 are less preferredbecause some degree of spacing is desirable to diminish their couplingforce (and thereby the resulting frictional force against translation ofeither the shuttle 20 or the magnetic guide 130) when stronger couplingto overcome an obstruction in the tube (via depressing button 23) is notrequired.

In the embodiments described, the coupling strength of the magneticfields between the primary magnetic elements 27 in the shuttle 20 andthe magnetic guide 130 within a tube received in the tube passage 40 canbe adjusted by adjusting the radial position of the primary magneticelements 27. The foregoing embodiments also disclose two primarymagnetic elements 27 and two secondary magnetic elements 28. However, analterative embodiments the shuttle 20 may possess only one primarymagnetic element 27 opposing one secondary magnetic element 28 along acommon radius relative to the tube passage 40 as already described. Inaddition, the primary magnetic element(s) 27 need not be adjustable.Rather, the primary magnetic element(s) can be in a fixed position.

FIG. 15 illustrates a partial cross-sectional view of a shuttle 20 asalready described, but wherein the primary magnetic elements 27 are notadjustable. In this embodiment, the coupling strength between theprimary magnetic element 27 and the magnetic guide 130 will not beadjustable. This embodiment is desirable from an ease-of-manufacturestandpoint, though it will not possess adjustable coupling strength withthe magnetic guide 130 as in other disclosed embodiments.

Referring now to FIGS. 16-18, a clearance device 100 as described hereinis shown fitted to a chest tube 10 via a chest-tube fitting 92 thatensures a fluid-tight connection between the distal end of the shuttleguide tube 110 and the proximal end of the chest tube 10, whileproviding fluid communication between the chest-tube passageway and theguide-tube passageway 116. The chest tube 10 has a wall having an outercircumference and an inner diameter that defines a chest-tubepassageway.

With the clearance device 100 and chest tube 10 fitted together asdescribed above, the guide member 122, and the clearance member 124disposed at its distal end, may be advanced into and withdrawn from thechest tube 10 to assist in clearing debris therefrom as follows. In use,the magnetic guide 130 and the primary- and secondary magnetic elements27, 28 of the shuttle 20 are magnetically attracted and coupled to oneanother when the shuttle 20 is fitted or properly positioned over theguide tube 110. This results in coupling the magnetic guide 130 to theshuttle 20 via magnetic forces that act through the guide tube 110 wall.Consequently, longitudinally sliding or translating the shuttle 20 alongthe length of the shuttle guide tube 110 induces a correspondingtranslational movement of the magnetic guide 130 magnetically coupledthereto, and of the guide member 122 that is secured to the magneticguide 130. In FIG. 16, the shuttle 20 (shown schematically) isillustrated in a first position, in contact with the shuttle stop 150.The length of the guide member 122 between its distal end and the pointwhere it is secured to the magnetic guide 130 is preferably selected tosubstantially equal the length of the chest tube 10 plus the lengthcorresponding to the distance between the shuttle stop 150 and the pointwhere the chest tube 10 engages the fitting 92. In this embodiment, whenthe shuttle 20 is positioned against the shuttle stop 150 (having themagnetic guide 130 in tandem therewith along the guide-tube 110 length),the clearance member 124 at the distal end of the guide member 122 isdisposed within the chest tube 10 adjacent to its distal end and doesnot emerge from the chest tube 10 into the body cavity. In a preferredembodiment, this is the first position of the clearance member 124,where it normally rests when the clearance device 100 is not being usedto actively remove debris from the chest tube 10.

In operation, with the chest tube 10 (its distal end) inserted in a bodycavity of a patient and the shuttle guide tube 110 being connected to asuction source 200 at its proximal end, fluid from the body cavity isdrawn into and through the chest-tube passageway, then through theguide-tube passageway 116 to be collected or disposed of in any suitableor conventional manner, such as in a conventional collection canister(not shown). (Alternatively, as noted above the guide tube 110 may bebranched from the main suction circuit defined between a medical tube 10and a vacuum tube 210, in which case fluid from the body cavity will bedrawn primarily through that main suction circuit and not through theguide tube 110). In the illustrated embodiment, the clearance member 124is in the form of a wire loop that scrapes the inner diameter of thechest tube 10 as it translates along the chest-tube 10 length.

As noted above, the clearance member 124 (e.g., a loop) is normallydisposed adjacent the distal end of the chest tube 10 inside thechest-tube passageway. To help clear the chest tube 10 of clots andother debris 400 accumulated therein, the shuttle 20 is disposed overthe tube 110, so that it is magnetically coupled with the magnetic guide130 within the tube 110. When so fitted, and once it is magneticallycoupled with the magnetic guide 130 within the tube 110, a nurse,physician, or other operator then pulls the shuttle 20 proximally alongthe length of the guide tube 110, toward the tube's 110 proximal end.The attractive magnetic force between the magnetic guide 130 and theprimary- and secondary magnetic elements 27, 28 of the shuttle retainsthe magnetic guide 130 in tandem with the shuttle 20 as the lattertranslates proximally. This in turn draws the guide member 122 andclearance member 124 proximally through the chest-tube passageway asseen in FIG. 17. As the clearance member 124 is drawn proximally, itengages clot material and other debris 400 in its path and forces suchmaterial and debris proximally (FIGS. 17, 18), toward the proximal endof the chest-tube passageway and ultimately out of that passageway, intothe guide-tube passageway 116 (FIG. 18). To carry out this operation,preferably the operator grasps the shuttle 20 with one hand and theproximal end of the guide tube 110 with the other hand so that thepulling force applied to the shuttle 20 is applied against acounter-force applied to the tube 110 via the other hand, and notagainst the sutures retaining the chest tube 10 in place in the patient.Alternatively, the same objective can be achieved by grasping adifferent portion of the guide tube 110, or the shuttle stop 150, withthe other hand before sliding the shuttle 20. Optionally, the clearancemember 124 can be alternately withdrawn and advanced from/into thechest-tube passageway to help break up clot material or other debris, aswell as to aid in drawing such debris proximally. Once the clearanceoperation has ended, the shuttle 20 may be used to restore the magneticguide 130, and consequently the clearance member 124, to its restingposition.

In case additional translational force is desired to traverse ordislodge a robust clot within the chest tube 10, the user can depressthe button 23 on the shuttle 20 to radially advance the primary magneticelements 27 toward the tube passage 40 therein, thereby strengtheningthe field between the shuttle 20 and the magnetic guide 130.

In the embodiments where such a button 23 is provided, it has beendescribed as actuating both the primary magnetic elements 27 shown inthe figures simultaneously. However, in select embodiments one primarymagnetic element 27 can be normally (or full-time) fully radiallyadvanced (or seated) toward or against the tube passage 40 of thepassage body 24, wherein actuation of the button 23 advances (orwithdraws) a second (or more) primary magnetic element(s) 27 to adjustthe coupling field strength. Or a plurality of buttons 23 as describedcan be provided, one for each primary magnetic element 27 so that thosemagnetic elements 27 can be individually and selectively radiallyadvanced in order to adjust the coupling strength with the magneticguide 130 within a tube received through the tube passage 40. Inaddition, while the button 23 has been described as a depressible button23, it be replaced with a rocker switch or another kind of switch toradially advance the primary magnetic element(s) 27. Optionally, forexample, the button 23 (or other switch) can include a locking featureto lock it in the fully radially advanced position (or in a different,e.g. user-selected degree of advancement) if desired.

As will be appreciated, while the shuttle 20 is being used to actuate aclearance member 124 within a medical tube 10, if it becomes de-coupledfrom the magnetic guide 130 within the guide tube 110, the shuttle 20and the magnetic guide 130 may be magnetically re-coupled by advancingthe shuttle 20 forward (or backward) until magnetic coupling isre-established. Alternatively, the operator may squeeze the chest tube10 or guide tube 110 to manually engage the guide member 122 through thetube wall and hold it in position while the shuttle 20 is translated soas to magnetically re-engage the magnetic guide 130 through theguide-tube 110 wall. In addition to facilitating translation of theguide member 122 via magnetic coupling between the (magnetic elements ofthe) shuttle 20 and the magnetic guide 130, the disclosed embodimentsalso facilitate rotation of the guide member 122 within the chest tube10/guide tube 110 by rotating the shuttle 20 about the exterior of thattube. The transversely aligned magnetic fields from the respective andopposing first and second magnetic elements 27, 28 within the shuttle 20are magnetically coupled to the magnetic guide 130 in a fixedorientation. Therefore, rotating the shuttle 20 about the tubecorrespondingly rotates the magnetic guide 130 (and the guide member 122to which it is attached) within the tube as a result of that fixedorientation. This may be useful to help clear obstructive debris withinthe tube, as well as for navigating obstructions or tortuosity resultingfrom curves or bends in the tube (for example due to kinks therein).

Although the invention has been described with respect to certainpreferred embodiments, it is to be understood that the invention is notlimited by the embodiments herein disclosed, which are exemplary and notlimiting in nature, but is to include all modifications and adaptationsthereto as would occur to the person having ordinary skill in the artupon reviewing the present disclosure, and as fall within the spirit andthe scope of the invention as set forth in the appended claims.

What is claimed is:
 1. A device for clearing obstructions, comprising: ashuttle defining a tube passage configured to accommodate a tube thereinand adapted to translate along a length of said tube when accommodatedin said tube passage, the shuttle comprising a first primary magneticelement aligned so that a first primary field axis of a first primarymagnetic field thereof is aligned substantially perpendicular to alongitudinal axis of said tube passage when viewed from a side of saidshuttle, said first primary magnetic element being adjustable between afirst position remote from the tube passage and a second positionproximate the tube passage.
 2. The device of claim 1, said shuttlefurther comprising a second primary magnetic element aligned so that asecond primary field axis of a second primary magnetic field thereof isaligned substantially perpendicular to the longitudinal axis of saidtube passage when viewed from the side of said shuttle.
 3. The device ofclaim 2, a North pole of said first primary magnetic element facing saidtube passage, and a South pole of said second primary magnetic elementfacing said tube passage.
 4. The device of claim 3, further comprising atube received in said tube passage and having a magnetic guide therein,wherein said first primary field axis is substantially aligned with aSouth-pole terminus of said magnetic guide along said longitudinal axis,and said second primary field axis is substantially aligned with aNorth-pole terminus of said magnetic guide along said longitudinal axis.5. The device of claim 1, said shuttle further comprising a firstsecondary magnetic element aligned so that a first secondary field axisof a first secondary magnetic field thereof is aligned substantiallyperpendicular to the longitudinal axis of the tube passage when viewedfrom the side of said shuttle.
 6. The device of claim 5, said firstprimary magnetic element and said first secondary magnetic elementopposing one another relative to said tube passage such that the firstprimary field axis and the first secondary field axis are radiallyaligned relative to said longitudinal axis of said tube passage.
 7. Thedevice of claim 6, further comprising a tube received in said tubepassage and having a magnetic guide therein, wherein said first primaryfield axis and said first secondary field axis are substantially alignedwith a South-pole terminus of said magnetic guide along saidlongitudinal axis.
 8. The device of claim 5, said shuttle furthercomprising a second secondary magnetic element aligned so that a secondsecondary field axis of a second secondary magnetic field thereof isaligned substantially perpendicular to the longitudinal axis of saidtube passage when viewed from the side of said shuttle.
 9. The device ofclaim 5, wherein the first secondary magnetic element is fixed withinthe shuttle.
 10. The device of claim 5, further comprising a secondarymagnetic shield arranged adjacent to an exposed surface of the firstsecondary magnetic element.
 11. The device of claim 1, furthercomprising a tube received in said tube passage and having a magneticguide therein, wherein a strength of magnetic coupling between themagnetic guide and first primary magnetic element is adjustable byadjusting the first primary magnetic element between said first andsecond positions.
 12. The device of claim 1, said shuttle furthercomprising a button that is spring biased radially away from said tubepassage, wherein depressing said button against the spring bias urgessaid first primary magnetic element from the first position toward thesecond position.
 13. The device of claim 1, further comprising a primarymagnetic shield arranged adjacent to an exposed surface of the firstprimary magnetic element.
 14. The device of claim 13, the shuttlefurther comprising a lateral magnetic shield that extends from onelateral side of the tube passage to an opposing lateral side of thepassage.
 15. The device of claim 14, the shuttle further comprising apassage body that defines said tube passage, said lateral magneticshield comprising ferromagnetic material and being seated on a fin thatextends laterally from said passage body, said fin being dimensioned topreserve a shape of said lateral shielding against deformation inducedby said first primary magnetic field.
 16. The device of claim 15, thefin comprising a protuberance configured to fit within an aperture ofsaid lateral magnetic shield.
 17. The device according to claim 1, theshuttle further comprising a passage body that defines said tube passageand comprises a primary recess configured to receive the first primarymagnetic element.
 18. A device for clearing obstructions, comprising ashuttle adapted to translate along a length of a tube, said shuttlecomprising: a passage body defining a tube passage having a longitudinalaxis configured to accommodate a tube therein, and a firstprimary-magnet recess disposed outside the tube passage; a first primarymagnetic element received in the first primary-magnet recess and havinga first primary magnetic field emanating along a first primary fieldaxis that is radially aligned relative to said longitudinal axis; and abutton operable to slidably adjust the first primary magnetic elementwithin the first primary-magnet recess between a first position radiallyremote from said tube passage and a second position radially proximatesaid tube passage.
 19. The device of claim 18, said shuttle furthercomprising a first secondary magnetic element having a first secondarymagnetic field emanating along a first secondary field axis radiallyaligned with and opposing said first primary field axis relative to saidlongitudinal axis.
 20. The device of claim 19, said shuttle furthercomprising a primary magnetic shield arranged adjacent to an exposedsurface of the first primary magnetic element, a lateral magnetic shieldextending from one lateral side of the passage body to an opposinglateral side of the passage body, and a secondary magnetic shieldarranged adjacent to an exposed surface of the first secondary magneticelement, said lateral magnetic shield comprising ferromagnetic materialand being seated on a fin that extends laterally from said passage body,said fin being dimensioned to preserve a shape of said lateral shieldingagainst deformation induced by said first primary magnetic field. 21.The device of claim 19, said passage body further defining a secondprimary-magnet recess disposed outside the tube passage adjacent to andspaced from the first primary-magnet recess along said longitudinalaxis; said shuttle further comprising: a second primary magnetic elementreceived in the second primary-magnet recess and having a second primarymagnetic field emanating along a second primary field axis that isparallel to said first primary field axis and radially aligned relativeto said longitudinal axis; and a second secondary magnetic elementadjacent to and spaced from the first secondary magnetic element alongsaid longitudinal axis, said second secondary magnetic element having asecond secondary magnetic field emanating along a second secondary fieldaxis radially aligned with and opposing said second primary field axisrelative to said longitudinal axis; said button being operable tocommonly adjust both said first and said second primary magneticelements within the respective first and second primary-magnet recessesbetween said first position and said second position.
 22. A method ofclearing obstructions, comprising: translating a shuttle disposedoutside a tube along a length thereof to correspondingly translate anelongate guide member that is at least partially disposed within saidtube and magnetically coupled to said shuttle through a wall of saidtube, wherein a magnetic field emanating from the shuttle is alignedsubstantially perpendicular to a longitudinal axis of said tube whenviewed from a side thereof; and adjusting an amount of translationalforce available to translate a clearance member affixed to or formedwith said elongate guide member within the tube by adjusting a positionof a first magnetic element disposed within the shuttle; wherein theposition of said first magnetic element being dynamically adjustablebetween a first position remote from the tube and a second positionproximate the tube when the shuttle is translated along said tube.
 23. Adevice for clearing obstructions, comprising: a shuttle defining a tubepassage configured to accommodate a tube therein and adapted totranslate along a length of said tube when accommodated in said tubepassage; and a first primary magnetic element that is adjustable betweena first position remote from the tube and a second position proximatethe tube in order to adjust a coupling strength between the firstprimary magnetic element and a magnetic guide disposed within said tubewhen received through said tube passage.